2

I have a solar inverter. Previously I would just assume the line and pull it through required single phase breakers in the distribution box.
But I have noticed that both lines have voltage to ground. I.E. even though the consumer doesn't work when you switch the breaker off the voltage from the "neutral" is still there.
I have tried switching the neutral and line but it has the same result. Should the inverter supplied consumers have breakers that cut both line and neutral?

3
  • 3
    Chances are good that the output of your inverter is isolated, and that you measure voltage between either leg and "ground" only because there is weak capacitive coupling, and your meter, like all modern DVMs, has high input impedance. I am not qualified to talk about the safety aspect of connecting that output to...well... anything really, but I bet you could not get significant current to flow from either leg to "ground" if you tried. Nov 16, 2022 at 13:09
  • What does "consumers" mean in this context? Can you state the model of "solar inverter" so we can track what you are saying? Nov 16, 2022 at 23:14
  • Whats the size of the voltage? In my previous house, some 30 years ago. I wanted the steel beams grounded. The sparky did not want to, so he measured the voltage. It was over 100 volts on the steel girder which had several 230V cables running around it . But I dont think it would have much current capacity. Anyhow, since then the sparky always grounds the beams. They call it strapping now. Nov 17, 2022 at 1:24

1 Answer 1

2

If two things are electrically isolated from each other, the voltage between them is ???. Cheap DVMs are extremely high-impedance (hi-Z) and will report nonsense numbers between two disconnected things. This is not a concern, it's just "phantom voltage".

A Grid-Tie system should be isolated

First, if this is a grid tied system, the inverter should comply with UL 1741 aka IEC 62109 rules for grid following, and totally shut down and isolate when it is not connected to an electrical grid. This is mandatory and normal behavior.

As far as whether circuit breakers connecting solar disconnect the neutral, that varies among countries. Europe has been starting to require breakers disconnect neutral along with live. This makes sense, since they have "whole house" RCDs (weak GFCIs). A branch circuit with a neutral-earth fault would disable the entire house's electrical system, and if breakers only switched live, there'd be no way to isolate that circuit to get the power back on.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.